[Pathogenesis of hemorrhagic dengue: critical discussion of current hypotheses]

The major hypotheses which have been advanced to explain the pathogenesis of "dengue hemorrhagic fever" are reviewed. Because of the difficulty in applying the definition of "dengue hemorrhagic fever" proposed by the World Health Organization, most of the discussion deals only with the most severe form of dengue, "dengue shock syndrome", which may or may not be a subset of "dengue hemorrhagic fever". It is not clear if it is the virus or the host that plays the predominant role in the pathogenesis of the dengue shock syndrome. More specifically, there is considerable difference of opinion as to whether or not a prior dengue infection with a heterologous dengue serotype constitutes a risk factor for the development of the syndrome. The evidence cited in favor of the latter concept is discussed from a critical point of view.